A cementitious blanket is primarily used to create a durable erosion-resistant lining after hydration, while a geosynthetic clay liner is a low-permeability barrier that relies on hydrated bentonite and adequate confinement. They should not be treated as direct substitutes.
Define the primary design function
Use a cementitious blanket where the project needs a hardened, erosion-resistant lining around channels, ditches or slopes. Use a GCL where the design requires a confined hydraulic barrier as part of a containment system.
Check installation and exposure conditions
Cementitious blankets require controlled placement, hydration, joints and curing. GCL performance depends on subgrade preparation, overlaps, early hydration control, confinement and chemical compatibility.
Review the complete system
Neither product should be approved from a sample photograph or mass per unit area alone. Review supporting layers, penetrations, drainage, cover materials and the project acceptance plan.